Like bigandJean says...why not inside? I put one inside on the bed on top of a blanket protecting the bedspread and the other fits in the box of the truck, ahead of the 5th...that way if you are travelling in the rain they dont get dirty from the road grime backsplashing from being at the back of the trailer. The one in the box of the truck may get wet but it wont have the road grime being driven into the gears and all the components of the bike.